function greeter(person) {
    return "Hello, " + person;
}

function test(foo) {
    switch (foo) {
        case 1, 2: // equals 'case 2' - probably intended 'case 1: case2:'
            return true;
        case 3:
            return false;
    }
}

let user = "Jane User";
console.log("hello world");

document.body.textContent = greeter(user);